pirkhurst



10 SheetsSheet 1.

(No Model.)

E. G. PARKHURST. BREEGH MECHANISM FOR ORDNANGE. No. 512,743. PatentedJan. 16, 1894.

Witnesses: [fiver 2Z0]? a Edward G Parlchumt.

p- By his flttarizey, 0% $756 (No Model.) 10 Sheets-Sheet 2. E. G.PARKHURST.

BREEGH MECHANISM FOR ORDNANGE.

No. 512,743. Patented Jan. 16,1894.

Fly. 4:

Witnesses 1O SheetsSheet 3.

(No Model.)

B. G. PARKHURST. BREEGH MECHANISM FOR ORDNANGE. No. 512,743. PatentedJan. 16, 1894.

Wz'mess es [72 z/en tor: X $440M Edward 65 Pam/#2117 56. fly izzls"flzforzzey,

(No Model.) 10 Sheets-Sheet 4 E. G. PA URST. BREEGH MEOHAN 0R ORDNANGE.

C, B v V (No Model.)

B. G. PA'RKHURST.

10 SheetsSheet 5.

BREEGH MEGHANISM FOR ORDNANOE.

- Witnesses:

Patentea Jan. 16, 1894.

(No Model.) 10 Sheets-Sheet 6.

E. G. PARKHURST..

BREECH MECHANISM FOR ORDNANGE.

No 512,743. Patented Jan. 16,1894.

F1916 my 17 Fly. 18.

rf V 4'3 3 46 a 9 48 50 45 I Witnesses: fnyenwr:

Edward 6; Park/21019:

(No Model.) 10 Sheets-Sheet 7. E. G. PARKHURST.

BREEUH MEGHANISM FOR ORDNANOE. No. 512,743. Patented Jan. 16,1894.

(No Model.) 10 SheetsSheet 8.

E. G. PARKHURST.

BREEOH MECHANISM FOR ORDNANOE.

No. 512,743. Patented Jan. 16, 1894.

'l Vz'rnesses: [n Men 60/: g 75110 6 mwum// Edward GPark/zurst K By his.flltorney,

OZM KE@& i

10 SheetsSheet 9.

(No Model.)

B. G. PARKHURST. BREEGH MECHANISM FOR ORDNANGE. No. 512,743. PatentedJan. 16, 1894.

Witnesses: Inventor: W Edward CiParkh urst.

.By/zz'sflzforzzey UMUZ I (No Model.) 10 Sheets-Sheet 10. E.G.'PARKHURST. BREEGH MECHANISM FOR ORDNANOE.

No. 512,743. Patented Jan. 16, 1894.

F1966. 1 19.67 7 5 C 8 q? Witnesses: Inventor: W g Edward G. Par/shuns;

By has flzzorzzey UNITED STATES PATENT OFFICE.

EDWARD G. PARKUURST, OF HARTFORD, UONNEUTICU'I, ASSIGNOR TO THEHOTCIIKISS ORDNANCE COMPANY, LIMITED, OF LONDON, ENGLAND.

BREECH MECHANISM FOR ORDNANCE.

SPECIFICATION forming part of Letters Patent No. 512,743, dated January16, 1894.

Application filed July 13, 1893. Serial No. 480,406. (No model.)

To all whom it may concern:

Be itknown that I, EDWARD G. PARKHURST,

a citizen of the United States, residing at Hartford, in the county ofHartford and State of Connecticut, have invented certain new and usefulImprovements in Breech-Loading Ordnance, ofwhich the following is aspecification.

This invention relates to breech-loading ordnance, and has specialreference to that class of ordnance, or rapid-fire guns, in which theopening of the breech, extracting the empty shell, and cooking the gunare accomplished by the movement of an actuating- 15 lever or crank-armin one direction, and the closing of the breech and making ready forfiring are accomplished by the reverse movement of the same lever.

My invention has for its object-to furnish an improved breech-mechanismfor rapid-firing guns of the class specified, having improved means foracluating the breech-block, and having improved devices and combinationsthereof for actuating, locking and releasing the cartridge-firingdevices and for effecting the assembling and disassembling of themechanism of the gun.

In the drawings accompanying and forming a partof this specification,Figure 1 is a plan view of a portion of a rapid-fire breechloading gun,of the so-called Hotchkiss type, embodying my present improvements. Fig.2 is a side elevation of the gun, as seen from below in Fig. 1. Fig. 3is a rear elevation of the same, as seen from the left-hand in Fig. 1.Fig. 4 is a front elevation of the same, as seen from the right-hand inFig. 1.

Figs. 5, 6, and 7 are side elevations, partially in section, of aportion of a'gun, showing the 40 breech-block and actuating-lever in thethree positions it successively occupies in the operation of opening thebreech-mechanism to insert a cartridge. Fig. 8 is a central verticalsection of the breech-block removed, taken 45 on the dotted line 0-0,Fig. 13, looking in the direction of the arrow, the firing-pin-arm beingshown in a retracted or cooked position. Figs. 9 and 10 are verticallongitudinal sectional details of the gun, taken on the dotted '50 lineff, Fig. 1, looking in the direction of the arrow, said figures showingthe firing-pinarm with its firing-pin in its forward and retractedpositions, respectively. Fig. 11 is a side elevation of thebreech-block, portions being broken away to more clearly show thefiring-pin-actuating mechanism. Fig. 12 is a front elevation of thesame. Fig. 13 is an under side view of the breech-block, thefiring-pin-actuating shaft being broken off. Fig. 14 is a side elevationof the breech-block, as seen from the right-hand of Fig. 12. Fig. 15 isa horizontal transverse section of the breech-block and mechanismcarried thereby, taken on dottedline a-a, as seen from the top in Fig.11. Figs. 16, 17 and 18 are crosssectional detail views, taken on dottedline g-g, Fig. 3, of the breech-block-actuating crank-shaft, its crank,the'actuating lever, and fastening devices, said figures showing threerelative positions of the locking-arm or 70 key with relation to thecrank-shaft. Figs. 19 and 20 are sectional detail views showing the stopfor limiting the movements of the breechblock. Figs. 21, 22 and 23 areenlarged rear views of the upper portion of the firing-pinarm and thefiring-pin, illustrating the successive positions of the firing-pinduring the insertion thereof into its seat in the firingpin-arm. Fig. 24is a vertical longitudinal section of a portion of the firing-pin arm,showing the firing-pin partially inserted. Fig. 25 is a sectional detailview of a portion of the breech-block, showing the manner of securingthe recoil-plate therein. Fig. 26 is a side elevation, partially insection, of the breech-block,showing the means for securing therecoil-plate therein. Figs. 27 and 28 are detail views, looking from theunder side of the breech-block, showing the manner of securing thefiring-pin-holding devices in the breech-block. Figs. 29 and 30 aresectional detail views showing the manner of securing thefiring-pin-shaft against longitudinal movement in the breech-block. Fig.31 is an irregular vertical sectional detail view of the breechblock,(partially in side elevation,) taken on dotted line hh, Fig. 33. Fig. 32is a front elevation of the breech-block. Fig. is a transverse sectiontaken on dotted line b-b, Fig. 31, looking downward. Figs. 3%, 35 and 36are detail views,in side and end elevation, of the firiug-pin-arm andfiring-pin. Figs. 37,

38, 39, and 41 are detail views of the firing-spring,firing-spring-supporting pin, and slide, or plunger, which constitutethe firingpin-actuating devices. Fig. 42 is a side elevation of thecocking-lever, its shaft being shown in dotted lines. Fig. 43 is afrontelcvation of said cocking-lever and its shaft, said figure showingthe spring detent-catch for securing the shaft in position in thebreechblock. Fig. 4% is a plan view of a portion of said shaft. Figs. 45and 46 are side and rear elevations, respectively, of the scar. Fig. .47is a plan view of a portion of the gun, showing the breech-piece withthe breech-block removed. Fig. 48 is a central vertical section of thesame, on dotted line ce, looking froni the under side of Fig. 47. Fig.49 is asimilar sectional view, looking from the opposite side in Fig.47. Figs. 50 and 51 are front and side elevations, respectively, of therecoil-plate locking-device. Fig. 51 is a rear view of the recoil platewith the fastening device removed. Figs. 52 and 58 are front and sideviews, respectively, of the fastening device which secures the recoilplate to the breech-' block. Figs. 51 and 55 are plan and sideelevations, respectively, of the breech-block-actuating lever. Figs. 56and 57 are side and front elevations, respectively, of thebreechblock-engagingcrank-arm anditsshaft. Figs. 58 and 59 are side andfront elevations, respectively, of the-locking-device for securing thebreech-block-actuating lever in place upon the crank-shaft. Figs. 60 and61 are side and front elevations, respectively, of the locking-arm orkey for the locking-device shown in Figs. 58 and 59. Figs. 62 and 63 areside and plan views, respectively, of the extractor. Figs. 64. and 65are end and side elevations, respectively, of the stop for limiting themovements of the breech-block. Fig. 66 is a rear elevation of theordnance, partiallyin section, showing the breech-block in the positionit occupies when first inserting the same in the breech-piece of thegun, or when removingit therefrom, the actuatinglever being broken off;and Fig. 67 is a side elevation of the same parts, of which someportions are shown broken away.

Similar characters designate like parts in all the figures.

For illustrating the application and mode of operation of my presentimprovement-s, I have shown the same appliedv to a rapid-fire gun of thewell-known Hotch'kiss type.

In the drawings, the usual barrel of the cannon or ordnance-piece isdesignated by B, and is shown formed integral with the enlargedbreech-piece C. If preferred, however, the barrel may be made separatefrom the breech-piece andinserted within the usual forwardly-en 'tendingjacket, in a well-known manner. Said breech-piece O is shown verticallyrecessed or mortised, as at 3, to form the sides 0, 0'', between whichis located the vertically-movable breech-block D. On the inner faces ofthe sides 0', 0', respectively,

of the breech, are formed the projecting guides or tongues 4 and 5,which enter the corresponding recesses 4', 5', rcspectively,in the outerside-faces of the breech-block I), which tongues and grooves form theguides for controlling the breech-block in its vertical movements. Saidtongues and grooves are shown formed somewhat inclined toa verticalline, as clearly shown in Figs. 14, 47, 48 and 49, so that the block D,as it is moved downward from the position shown in Fig. 5 to that shownin Fig. 7, will be carried rearward a short distance, thus relieving thepressure against the head of the cartridge (not shown) in thegun-barrel. Said backward inclined verti cal movements of thebreech-block carry the forward face of said block away from the forwardabutment face of the breech as the breech-block descends, the guidesbeing so disposed as to eflfect such relief-movement on the firstdownward movement of the breechmechanism. For this purpose the rear face6 of the breech-block is formed slightly at an angle with relation to aline at right angles to the axis of the gun, said face being inparallelism with the aforesaid breech block guides, whereas the frontface of said breechblock, and the front abutment-face of thebreech-piece C, are in parallel lines and substantially at right anglesto the bore of the gun-barrel.

The rearward wall 0 of the breech-piece which connects the side-walls Cand 0" back of the breech-block mortise, is shown cut away for a portionof its width and from the upper side downward to a point below the lineof the gun-barrel, to form an opening through which to insert thecartridges and remove the empty cartridge-shells in the usual manner; ateach side of said cartridge-opening, a portion of the wall remains toform the shoulders 7 and 8 for supporting the rearward face of thebreech-block when this is in its uppermost position ready for firing thegun.

'The front face of the breech-block is recessed and provided with arecoil-plate, 10, which is removably secu red in place by means of aspring-catcl1,designatedin ageneral way by S, engaging in a. recess, 13,in the inner face of one of the walls of said block, as will behereinafter more fully described. This recoil-plate is bored andrecessed, as shown at 14, in Fig. 10, to receive the forward end of thefiring-pin. When the breech-block D is in its uppermost position, asshown in Figs. 2, 3, 4, 5, 9 and 10, the forward face of therecoil-plate 10 stands close to the channel 15 for the cartridge-head,and as said breechblock is gradually lowered, it is withdrawn rearwardlyuntil (in the lowest position of the breech-block as shown in Fig. 7)said recoil-plate stands a short distance back from the line of saidcartridge-head channel. While the rear face of the breech-block alwaysmoves in line with the inclined shoulders or faces 7 and 8, (owing tothe guides4 and 5 being parallel therewith,) its front face, which restsICC snugly against the breech of the gun, only when said block iselevated, will, at the first descending movement of the breech-block,move backward away from the aforesaid position, thereby at oncerelieving the pressure of the cartridge-shell on the recoil-plate.

The vertical movements of the breech-block are accomplished by means ofthe hand-operated actuating-lever E, secured to a short shaft,16,that isjournaled inone of the walls, U", of the breech-piece. This shaftcarries on its inner end a crank, 17, capable of oscillation in arecess, 18, formed in the side of the breech-block, and is provided atits free end with a stud or crank-pin, 19, that enters and runs in acam-groove,cut transversely in the side of said block. This cam-groovehas a forward portion, 21, which is preferably concentric with the shaft16 when the breechblock is in its uppermost position, (see Fig. 5,) andhas a rearward oppositely-disposed portion, 22, which forms the camproper. By this construction of cam, it will be seen that, as theactuating-lever is drawn rearward from the position shown in Fig. 2 tothe position shown in Fig. 5, the stud or pin upon the crank will, forthe entire length of the throw of the crank 17 between the two positionsshown in the figures referred to, move idly in the cam-groove withoutmoving the breechblock with relation to the breech of the gun. As soon,however, as the crank-pin 19, in its backward movement, passes the pointor position it occupies in Fig. 5, it enters the rearwardoppositely-curved portion, 22, of the cam-groove, and immediately comingin contact with the lower wall of said groove, thereby moves thebreech-block quickly downward to the position shown in Fig. 7. When themovement of the actuating-lever is reversed, the breech-block will bequickly moved upward to its closed position, the reverse of its movementin the operation of opening the gun previously described.

The range both upward and downward of the vertical movements of thebreech-block is positively limited by a stop-pin, 24, which passesthrough one side of the breech-piece and enters a recess, 25, in theleft-hand side of the breech-block, as clearly shown in Figs. 1, 3, 4,19, 20 and 66. As a means for removably securing this stop-pin in thebreechpiece, the said step is shown provided with the detent-catch 26,which, as shown in Figs. 19, 64 and 65, is let-in to the side of theshank, 24', of the stop and has a fixed bearing in a hole in the head ofsaid stop. The inner free end, 26', of the detent-cateh is provided witha projection adapted for engagement with catches or notches, 27, formedin the wallsof the recess or bore 28, Figs. 19, 20 and 47, in which theshank of the stop is seated; said detent-catch 26 is in the nature of aspringcatch and operates to normally hold said stop against accidentaldisplacement. In the drawings, I have shown two annular catchgroovesformed in the seat of, and concentric piece.

therewith, so that, when it is desired to withdraw the stop fromengagement with the breech-block, as in Fig. 9, to the position shown inFig. 20, for permitting the breechblock to be removed from thebreech-piece of the gun, a sudden pull upon thehead of the stop is allthat is required, the detent-catch projection 26", owing to its shape,being readily withdrawn from the inner catch-groove to the enter one.

For the purpose of removably securing the crank shaft in thebreech-piece, and as a means for securing the crank-actuating lever sothat it will, during a portion of its oscillation, inoperatively, and inthe balance of its oscillation, operatively, engage the crankshaft, (thepurpose of which will be hereinafter fully explained,) I provide a shortshaft, 16, with the crank 17, preferably formed integral therewith, andinsert said shaft in its bearing in the breech-piece through thevertical mortise 3 in said breech-piece, said shaft being of suificientlength to project a short distance beyond the outer face of said breech-Said shaft is shown reduced in diameterat its outer end, as indicated at16', to form a journal for the actuating lever E, which, in assemblingthe parts, is slipped on over the end of said shaft and is fitted toeloselyen gage, but freely move upon, said jou rnal. The extreme outerend of the shaft 16 is squared or flattened on one or more sidesthereof, which squared end is adapted to receive a coupling orlocking-device, designated in a general way by F, which coupling, aswill be hereinafter more fully described, is locked into engagement withthe shaft and has a projection, 30, to engage and limit the extent offree movement of the actuating-lever upon and with relation to theshaft. In the present instance, the shaft 16 has the extension, 16 ofthe lever-bearing 16 or extreme outer end of the shaft, flattened onthree sides, designated by 31, 31', and 31 respectively; the fourthside, designated by 32, is shown forming a continuation of thecylindrical outer surface of the shaft; and in this side (which ispreferably left full as shown, and not cut away) is formed atransverseshaft-lock notch, 33, for receiving the working-end or key of thecoupling or shaft-lock F, as hereinafter more fully described. Theshaft-lock or coupling, designated in a general way by F, consists of aplate, 34, having a transverse bearing-opening, 34!, to correspond withand fit the squared portion of the crank-shaft 16, and has atransversely-projecting lug, 30, radially disposed with relation to theaxis of the shaft when said locking-plate is in position thereon; whichlug, when the parts of the crank-shaft are assembled, extends betweenthe cars 35, 35 upon the actuating-lever; these ears are radiallydisposed with relation to the bearing-axis of said lever, and formabutting faces to engage the faces of the lug or projection 30 upon thehub 34, during the movement of the said actuating-lever. As will be seenby the drawings, the lug 30- upon the crank-lock hub 34 is of a V-shapcdform, its sides being about radial to the axis of its bearing; and thespace between the cars 35, 35' of said lever is correspondingly V-shapedand of greater width. This construction allows a limited free movementof the actuating-lever with relation to said lug 30, so that, during thefirst movement of the lever, it meets with no resistance, but aftertraversing a given are, the abutment-face 35' (owing to the moment-umattained by the lever in its unobstructed swinging movement) strikes thelug 30 with a sudden and considerable force, thereby quickly startingthe breech-block from its impinged closed position.

The crank-lock hub 34 is recessed centrally at its upper outer edge, asshown at 36, to form ears between which is pivoted alockingplate, 37,which has a curved resilient projection or arm, 37', extendingunderneath and impinging on the hub when this is secured in positionupon the shaft 16, as shown in Fig. 2. The recess 36, which forms theseat for the locking-plate 37, communicates with the bearing-opening,34', in said hub, the purpose of which feature will be obvious. Thelocking-arm 37, in its preferred form, as most clearly shown in Figs. 58and 60, has on the inner side thereof thelock-catch or bolt-end 38,adapted for engaging in the aforesaid transverse slot orlock-notch 33 inthe shaft 16. In assembling thecran k-shaft and said accessory parts,assuming the crank to be in position in its bearing in the breech-pieceand the actuating-lever in proper position upon the journal 16', thelocking-hub, with its locking-plate in an inoperative position, isslipped upon the squared end of the shaft with its lug 30 projectingbetween the cars 35, 35', of the actuating-lever, after which thelocking-arm is depressed so that the lock-catch 38 thereof extends intothe notch 33 in the shaft; the curved arm 37' of the locking-arm, duringthis movement, coming under and tightly impinging the lower face of thelocking-plate, thus preventing lateral displacement of the locking-armand at the same time securing the locking-device F and theactuating-lever E against longitudinal movement upon the shaft 16. Theoutward movement of the locking-platefrom the closed position shown inFig. 16 to the open position shown in Fig. 18, is limited by theprojecting end or stop-arm 39, which engages against the stop-face 40 ofthe locking-plate 34, as shown in Fig. 18. When the locking-plate is inits closed or working-position shown in Fig. 16, the outer end, 41, ofthe yielding lever-arm'37' thereof' extends beyond a central line,115-:0, drawn through the fulcrum of the locking-arm and axis ofthelocking-platc, and yieldinglygrasps shaft as shown in Figs. 1 and 16,the operator' may quickly withdraw the same by throwing the locking-arm37 out of engagement with its locking-notch in the shaft, which willallow both the locking-device F and the lever to be withdrawn andreplaced practically by one operation, without the necessity ofreleasing the grasp upon either of the pieces so removed or replaced. Bymeans ofthe construction and mode of assembling thus described of theseveral parts, it is practicable to have these so fitted as to be freelyassembled and disassembled by hand without having any objectionable playof one part upon the other; also,

the use of small separable details, such as the normally-loose pins orscrews heretofore largely used in this class of devices, is entirelyavoided, the device herein shown having only one pin, the pivot-pin forthe locking-arm; and this, being firmly driven into the lockingplate,is, therefore, normally non-separable.

The crank-attachment here described constitutes the subject-matter of aseparate application, Serial No. 481,479, filed July26, 1893.

Formed upon the hub of the breech-block actuating lever, as clearlyshown in Fig. 55, is a cam or projection, 35 adapted for engagement witha cam lever, 43, upon the firing-pin shaft, when the saidactuating-lever is moved to open the breech to thereby partially rotatethe firing-pin shaft to cock the gun during the descent of thebreech-block, substantially as hereinafter more fully set forth.

The firing-pin shaft, designated in a general way by G, is journaled atits ends in transverse bearings formed in the side-walls, cZ-d, of thebreech-block D, one of said journal-bearings being formed in a tubularprojection, 42, which may be formed integral with and extending beyondthe out-er face of the side-wall 01', said tubular bearing supportingone end of the said shaft nearly its entire length. Secured to, orformed integral with, this end of the shaft G, is a cam-lever, 43, whichcam-lever,.when the parts are as sembled, lies in the plane of movementof the cam 35 upon the breech-block-actuating lewar, and is adapted tobe actuated thereby during the opening movement of said lever forpartially rotating the said shaft G to re- IIC tract the firing-pin-arm,as will be hereinafter more fully described; this cocking operationtakes place, of course, during the descent or opening movement of thebreech-block. The firing-pin shaft G is shown reduced at its lefthandend, as shown at 44, to form ashoulder, 45, adapted to abut against theinner face of the side-wall d of the breech-block to preventlongitudinal movement of said shaft in one direction; said reduced end44 forming the journal for this end of the shaft, and being ofsufficient length to extend a short distance beyo d the outer face ofsaid side-wall d, as clearly shown in Fig. 12. Formed longitudinally inone side of the journaled end, 44, of the shaft G, is a recess, 46,inwhich is secured a resilient detent-catch, 47, that is secured at itsinner end in the recess 46 by means of a pin, 48, extending into atransverse hole in said shaft; said detent-catch has, at its extremeouter free end, a laterally-projecting catch, or hook, 49, which, whenthe shaft is extended into its hearings in the side-wall of thebreech-block, will spring upward and engage with the outer face of theside-wall (Z, and thus secure the shaft against longitudi nal movement.A portion of the central part of the shaft G will be cut away at itssides, as shown at 50, preferably on that portion adjacent to thebearing-end, 44, to form a squared or hexagonal journal adapted toengage in the corresponding bore, 51, of the hub, 52, of the firing-pinarm H; which arm carries the firing-pin I.

The firing-pin arm,designated in ageneral way by H, consists of the hub52, which, in practice, is made of a length equal to the distancebetween, and has a hearing at its ends against, the inner faces of theside-walls, d-d', of the breech-block; which bearing prevents movementofsaid armlongitudinally of its shaft. Said hub 52 is suitably boredlongitudinally for non-rotative engagement with its actuating-shaft G,the construction being such as to permit these parts to be readilyassembled. Formed upon the hub 52, at one side of the firing-pin arm, isa cam-lever or curved projection, 55, which, as will be hereinafterdescribed, is adapted for engagement with the firing-spring-actuatedslide K during the rotary or turning movement of the firing-arm shaft Gto compress said spring preparatory to firing. Formed upon the said hub52, at the opposite side of said arm, is a sear-catch, or projection,56,adapted to be engaged by the catch, 57, of the searL, for holding theshaft G, with its firing-pin arm and firing-pin,in a retracted positionready to fire the gun.

As shown most clearly in Fig. 15, the breechblock is vertically recessedat its lower end, as shown at 58, and 60, to form vertical walls orpartitions; between which walls the sear L, the catch 56 upon the hub ofthe firing-pin arm, the tiring-pin arm and its cam 55, respectively, arelocated and move during the rotation of the shaft G. The breech-block,

or guide M.

as shown at 61 in Fig. 31, is vertically bored at its under side, nearits rear end, in a line with the slide-retracting cam upon theflring-pinshaft, to receive, and form a bearing for a vertically-reciprocatingfirmg-pmactuating slide K. v

The firing-pin-actuating devices cons sentially, of the firingspring M,the suppor ing-stud or pin, M, therefor, and the reciprocating slide K.This slide K is, preferably, tubular in shape, for forminga casing forthe firing-spring, and at its upper end bears upon said spring, as shownin dotted lines in 111g. 40. This slide is fitted to have free verticalmovement in the bearing 61, before referred.

to, and has, at its lower end, an outwardlyprojecting arm, 62, adaptedfor engagement with the cam-face, 55, of said firing-pin arm. Thefiring-spring is supported at its lowerend upon an elongatedbearing-plate or head, 63,- on the lower end of the spring-supporting pmAs a means for securing the hring-spring slide and supporting-pin inplace, the bore or recess 61 is enlarged diametrically at the lower end,where it extends through the bottom-plate of the breech-block, asclearlyshown in Fig. 27, to form an annular recess in the bottom wall of thebreech-block between its inner and outer edges, as shown in Fig. 25, toform annular flanges, 64, 64", for supporting the said bearing-plate 63Ihrs annular recess is, practically, of a diameter equal to the greatestdiameter of the bearingplate 63, and the elongated opening in the bottomwall of the breech-block corresponds substantially to the shape of saidbearingplate.

The elongated opening, 61, in the bottom plate of the breech-block has acontinuat on, or extension, 67, at one side, of sufficient length topermit the projecting arm 62 upon the slide K to be insertedtherethrough,sa1d arm- 62 being of less width than the diameter of theslide, which slide is of a diameter approximately equal to the width ofthe opening 61 aforesaid. By this construction and arrangement, it willbe seen that the slide K, firingspring M and spring-supporting pin maybe inserted as one piece through the opening 61 and secured in properposition in the breech-block, it simply being necessary, after the saidparts are inserted and the bearing-plate 63 of the spring-supporting pinis in alignment with the annular recess above the flanges 64, 64, toturn the bearing-plate 63 one-quarter of a revolution, to the positionshown in Fig. 28, the ends of said bearingplate, in this position,overlying the flanges 64, 64', and being held thereby in position.

As a means for preventing accidental turning of the spring-supportingpin and connected parts, the bearing-plate 63 has an angular axialprojection, 68, at its outer face, herein shown as square, which proection is of a size to closely' fit between the adjacent edges of theflanges 64, 64 when the parts are assembled and the bearing-plate is inthe position shown in Fig. 38. For convenience in turning saidbearing-plate andsp'ring-sup porting pin to disassemble the parts, theprojection 68 of said bearing-plate is preferably knurled or corrugatedon its outer face to form a head capable of being turned by the fingerof the gunner by frictional engagemen t. By this construction andarrangement of the firing-pin-actuating devices just-described, the saidparts may be quickly removed in an assembled condition, as one piece,for the purpose of cleaning or forthe replacement of defective parts,andquickly replaced in operative position, it simply being necessary, whenremoving the said parts, to turn the bearing-plate 63 one-quarter of arevolution in its seat, when said parts will drop out; and afterinserting the same, as before described, a reverse movement of thebearingplate will secure the parts against accidental displacement.

As a means for holding the firing-pin lever and firing-pin in aretracted or cooked position, or in the position shown in Fig. 10, thehub 52 of the firing-pin lever has, as before stated, a catch, 56,adapted to engage with a notch or catch, 57, formed on the forward sideof the sear L, which sear is pivotally secured to the breech-block inthe vertical recess 58, above the said catch 56, by a journalpin, 65.The pivotal point, 65, of the sear is above and slightly in advance ofthe axis of the shaft G, and the sear has a depending curved arm, 66,which extends below said shaft and has a loop or eye adapted to beengaged by a hook or other suitable device, or by the finger of thegunner, to retract said sear for disengaging its catch 57 from thefiringpin lever. As a. means for normally depressiug said sear andretaining it in locked engagement with the hub ofthe firing-pin lever, asear-spring, 78, is provided, as shown in Fig. 11; which spring isseated in a suit able recess at 79, Fig. 11, in the breech-block, and atits lower end bears against the upper face of the sear; an annularrecess being preferably formed, at 79', in the upper face of the sear,to provide a seat for the sear-spring and prevent lateral movementthereof.

The head of the firing-pin lever (which is shown slightly enlarged) istransversely bored as shown at in Fig. 24, to receive the firingpin I.Located within the bore, 70, of the head of the firing-pin lever, is atransverse wall or partition, 71, divided or recessed centrally, as at72, to form side-flanges for preventing longitudinal movement of thefiring-pin. The firing-pin Iconsists of a main cylindrical body, 73,having a conical flanged head, 73, at its forward end, and having a.central firingpoint, 74, for striking the cap of the cartridge.

The body-portion of the firing-pin is transversely and longitudinallyrecessed or centrally divided, as shown at 75, and has, near its rearend, at opposite sides, two outwardlyprojecting flanges, 76, adapted toengage the rear face of the flanges formed by the wall 71 when the pinis secured in position. The bore 70 in the rear of the wall 71 isirregular in form, to provide cam-faces, at 77 and 77', between whichthe flanges, 76, of the firingpin will be normally held (when saidfiringpin is in place) against rotary movement. In securing thefiring-pin in position in'the head of the firing-pin lever, the rearflanged end of said firing-pin is first inserted within the bore 70 ofthe said firing-pin lever with its flanges in a vertical plane, as shownin Figs. 23 and 24,and moved backward until the flanges 76 pass throughthe central opening in the wall 71; in this 7 position, the flanged head73 will bear against the forward face of the head of the firing-pinlever, and the forward faces of the flange 76 will be slightly in therear of the rear face of the wall 71. Next, the firing-pin will beturned, either to the right or left, a quarter of a revolution from theposition shown in Fig. 23 to that shownv in Fig. 21, which turning ofthe firingpin will, in consequence of the cam-faces 77, 77, slightlycompress the rear end of the firing-pin, as shown in Fig. 22, allowingthe flanges to ride past the cam-promotion, and, after passing saidprojection, immediately expand and be seated in the camsha ped recesses,as shown in Fig. 21, thus locking the firing-pin against accidentalrotation and securelylocking the same in posit on longitudinally. Toremove the firing-pin, it is only necessary to turn the same fromtheposition shown in Fig. 21 to that shown in Fig. 26, by aquarter-revolution, and then withdraw it by a forward longitudinal pull.

Formed in the outer face of the left-hand Wall of the breech-lock, nearits front end, is the vertically-located extractor-cam-groove 80, whichbegins at the upper outer edge of the breech-block, extends downward fora short distance in parallelism with said guiding-groove 4', is thenceforwardly curved, as shown at 81 in Fig. 14,to form the extractorcam,andbelow that again continues downward in parallelism with said guding-groove to its terminus approximately midway of the length of saidblock. The engagement of the extractor P with the extractor-cam iseffected by means of a stud or projection, 82, formed on the outer sideof the extractor, wh ch stud fits in said cam-groove to slide all] afterthe usual manner of this class of devices. The extractor, designated ina general way by P, and shown in detail in Figs. 62 and 63, consists ofa tongued plate, 83, fitted to slide in a corresponding groove orchannel, 84, formed in the inner face of the left-hand wall 0' of thebreeclrpiece C, as clearly shown in Fig. 48 of the drawings. At itsforward end the extractor is provided with an inwardlyprojecting hook,85, which on the forward movement of the same enters into a recess, 86,in the bore of the gun-barrel, which recess is a continuation of achannel 84 formed in the breech-piece. hen the extractor is in itsforward position, the point of its book lIO stands justforward of .therim of the cartridge, as shown in dotted lines in Fig. 47. On the firstdownward movement of the breech-block, (the ways of this being inclineddownwardly andbackwardl y as hereinbefore described,) the face-plate, orrecoil-plate, 10,

is withdrawn with the breech-block slightly from the head of thecartridge-shell, and as the breech-block mechanism continues itsdownward movement, the aforesaid stud 82 travels in the cam-groove fromits lowest position, shown at r in Fig. 2, at the lower end of thecam-groove 80, and first strikes the forward face of the cam 81 (at thepoint marked 3 in Figs. 2 and 14), and as said cam-face is there butslightly inclined from the vertical, the extractor is subjected to apowerful backward throw, thereby forcibly starting the cartridge-shellfrom its seat in the firingchamber or bore of the gun-barrel. As thedownward movement of the breech -block mechanism continues, theincreasing inclination of the extractor-cam rapidly accelerates therearward movement of the extractor, thereby imparting a rapidlyincreasing -velocity to the rearwardly-moving cartridgeshell, so thatwhen the upper end of the breechblock passes below said cartridge-shell,the shell has already acquired such momentum as to pass over the block.and to a considerable distance rearwardly of the gun, being thusfinally disposed of.

As a means for securing the recoil-plate pin in the front face of thebreech-block, the recess in the breech-block for'receiving therecoil-plate is shown of a dovetailed form, and

the side-edges of the recoil-plate are beveled, as at 88, to fit thedovetailed recess of the breech-block, as shown in detail in Fig. 50. Asshown in Fig. 51, the recoil-plate is bored transversely, nd iscounter-bored at the rear face concentric thereto to form a counter-sunkbearing for the fastening device S. Said said recoil-plate.

counter-bored bearin g for the fastening device S extends through theouter edge of the recoil-plate, as shpwn' in Fig. 50, and is on one sideslightly elongated, diametrically, to form a catch-notch, 12, with whicha catchupon the fastening device engages to hold the catch againstlateral displacement after the recoilplate is secured in thebreech-block. This fastening device, S, consists of a disk-shaped 1plate, 89, planed off at one side, as shown at 90, to correspond with,and lie in the planeof, the outer edge of the recoil-plate wheninserting said plate preparatory to securing it in place in thebreech-block, and has a cylindrical axial projection adapted to extendthrough the transverse bore or journal-bearing formed in therecoil-plate with its outer face substantially flush with the outer faceof The disk-shaped fasteningplate 89 is made to fit the counter-bore inthe recoil-plate and adapted to be turned therein (after the plate isinserted in the breech-block) by means of a screw-driver or other toolapplied to a notch or nick in the front face of its journal 91. At oneside of thejournal 91,

this is notched, as shown at 91, to form a denear the outer edge of thefastening-plate,

tent-catch, 92, which will normally project slightly beyond theperipheral line of the fastening-plate. In assembling these parts, thefastening-plate will be inserted 1n 1ts bearing in the recoil-plate withits plane side in alignment with the outer edge of said plate, afterwhich the plate will he slid into place in the breech-block, and thefastening-plate will then be turned a quarter of a revolution, bringingits edge 93 outward beyond the edge of the recoil-plate, and into therecess, 13, shown in Fig. 25 in the inner edge of, the outer wall of thebreech-block; at this time the detent-catch 92 will be released from itscompressed position and will enter the detentnotch formed in thecounter-sunk beartqg of the fastening-plate. This operation Wlll lockthe fastening-plate against accidental rotary displacement which mightoccur from constant vibration caused by concussion in firing. Theconstruction and arrangement thus described of said fastening-devicesecures a simple and effective means for attach-. ing the recoil-plateto the breech-block, and permits the parts to be quickly assembled anddisassembled.

The general operation of thebreech-loading ordnance isas follows:Assuming the gun to have been fired and the breech-mechanism to be inits closed position, as illustrated 1]) Figs. 1 and 2, the gunner,seizing the handle of the breech-block actuator, draws the same upwardand backward to draw the breechblock downward its full stroke to itsextreme lower position. The first movement of the actuator-lever is toturn freely without efiecting a movement of its shaft. After theactuator-lever, in its backward movement, has nearly reached theposition shown in Fig. 5, the abutment-face 35' thereof strikes theprojection 30 of the locking-device F secured to the shaft- 16, withconsiderable'force, thereby immediately rotating said shaft, togetherwith its crank 17; the projection 10 at the upper end'of said cranktraveling in the cam-groove 21 in the breech-block, strikes thecam-face22, and starts the breech-block from its closed position, the continuedrearward movement of the actuating-lever carrying said breechblock, bymeans of the crank-arm 17, to its lowest position. During said rearwardmovement of the actuating-lever, the cam 2:5 thereof strikes thefiring-pin-shaft actuating-camarm, and carries the same downward n anadial plane, thereby rotating the fir ng-pin shaft G, retracting thefiring-pin arm, and at the same time bringing the end of the cam 55(upon the hub of the firing-pin arm) 1n engagement with the arm 62 atthe lower end of the slide K, thus carrying the same downward andcompressing the firing-sprmg M. When the saidcam 55 has reached itsrequisite downment with the catch 67 upon the sear L, which tion, asshown in Fig. 10, in which positionthe parts are retained until thebreech-block is elevated by a reverse movement of the actuating-leverand is secured in a closed position ready for firing. After thebreech-block has been closed (a cartridge having been inserted while theblock is in its lowest position) and it is desired to discharge the gun,the lower end of the sear L is drawn backward, which releases its catch57 from the catch 56, when the stress of the firing-spring willimmediately force the slide upward, imparting a sudden rotary motion mthe cam 55 together with the shaft G, and throwingthe firing-pin fromthe position shown in Fig. 1-0 to that shown in Fig. 9, when the pointthereof comes in contact with the cap and discharges the cartridge.During the] downward movement of the breech-block, the cartridge-shellis extracted 'by the backward movement of the extractor P, ashereinbefore described.

By means of the construction of ordnance herein described, any and allofthe parts may be quickly removed and replaced without the use-of tools,thus permitting the gun to be quickly assembled and disassembled.

To insert the breech-blocki'nto the breech of the gun, thebreech-mechanism being assembled therein, the breech-block-actuatinglever will be thrown over to the position shown in Fig. 67, the stop 24,which limits the vertical movements of said breech-block, being held inthe position shown in Fig. 66,- after which'the breech-block will beinserted a short distance from the under side of the breech into therecess 3, until the cam-groove 21- comes into line with the crank-pin,19, of

the crank-arm 17, when said crank-arm, through themedium of theactuating-lever,

will be thrown backward until its projection 19 enters said cam-groove;after this, a continned upward movement of the actuating" lever willcarry the breech-block into the-po- I sition shown in Fig. 2, whenthestop 24 will be pressed inwardto engage in the stop-- groove 25 inthe breech-block, after'which the gun is ready for operation.

Having thus described my invention, 1 claim v 1. In breech-loadingordnance, in combination, a barrel having a verticallyrecessedbreech-piece, a vertically-sliding breech-block having a cam-shapedgroove in one side thereof and having vertical recesses to receive thefiring-pin-actuating mechanism, a breechblock-actuating shaft removablyj onrnaled in the breech-piece and having a breech-blockactuating-crankin engagement with the camshaped groove in the breech-block, anactuating-lever loosely mounted upon the shaft and having a cam forengagement with the cocki-ng-leverof the firin g-pin-actuatin g shaft,

a locking-device orcoupling removably se-' to engage with, and limit thefree movement of the actuating-lever upon the shaft, afiringpin-actuating shaft journaled in the breech block and having adetent-catch at one end for engagement with the breech-blockfio preventlongitudinal movement of the shaft, and having a cockingdever at theopposite end in position to be acted upon by the cam of theactuating-lever, a firing-pin arm removably carrying a firing-pin at itsupper end, said arm being secured to said shaft in non-rota.- tiveengagement therewith and having contiguous thereto a spring-com pressingcam and a catch for engagement with the sear to lock the shaft and armina retracted position, a spring-actuated slide in engagement with saidcam adapted for operating the firing-pin arm to fire the gun, and aspring-actuated sear pivotally supported in the breech-block and havinga catch adapted for engagement with the catch of the firing-pin arm tolock said arm in the retracted or cooked position, all co-actingsubstantially as and for the purpose described.

tion with the breech-piece adapted for-carryin g a sliding breech-block,of a sliding breech-block having a cam-way formed in one side thereof, acrank-shaft havinga crank-arm in engagement with said cam-way and havingating-lever and having its extreme outer end squared orangulariy-grooved transversely to receive a locking-device, anactuating-lever mounted upon said shaft adjacent to the breech-piece andcapable of a limited free movement on said shaft, and a coupling orlocking-device removably fitted to the squared or angular end of thesaid shaft and having a locking-arm capable of movement into and out ofengagement with the transverse recess in said shaft to secure the partstogether and prevent displacement, substantially as de: scribed. I

3. In breech-loading ordnance, the combination with the breech-pieceadapted for new ryinga sliding breech-block, and with the breech-block,of a crank-shaft journaled in said breech-piece and havinga crank-arm atcate said breech-block'and having its outer end cut away at its sidesand recessed or notched adapted for locking engagement with thetransverse recess in said shaft, whereby the parts are locked againstlongitudinal displacement and the lateral movement of the actuating-armwith relation to the shaft is limited,

substantially as described.

ating-lever and having apivoted locking-arm 2. In breech-loadingordnance, the combinaits outer end forming a bearing for an actuitsinner end adapted to engage and recipro- Y 4. .In breech-loadingordnance,'the combination with the breech-piece adapted for carrying avertically-slidin g breech-block, and with the vertically-slidingbreech-block having a cam-groove in its outer face, of, a crank-shaftjournaled in one side of the breech-piece and having acrank-arm at itsinner end in engagement with the cam-groove of the breech-block andhaving a squared or angular outer end witha transverse recess in oneface thereof, a breech-block-actuating lever fitted to said shaftbetween the squared or angular end thereof and the breech-piece, andcapable of a limited transverse movement thereon, an independentcoupling or locking-device in nonrotative engagement with the angularend of the crank-shaft and having a projection adapted for engagementwith the actuating lever to limit the transverse movement of said leverupon the shaft, and a locking-arm'pivoted to said coupling and having aprojection adapted for engagement with, and disengagement from thetransverse notch in the angular end-portion of the shaft, whereby saidpartsmay be readily-assembled and locked against longitudinal movementwith relation to the breech-piece, and may be readily disssembled andremoved from said breech- ,piece, substantially as described.

5. In breech-loading ordnance, the combinationjwith the breech-pieceadapted for carrying a sliding; breech-block and with the slidingbreech-block, of a crank-shaft journaled in the breech-piece and havinga crank-arm in engagement with the breech-block for raising and loweringthe same, and having acocking-lever anda cam to actuate the firing-pinmechanism,,a firing-pin-actuating shaft removably journaled in thebreech-block and having a cocking-lever at one end in position to beoperated upon by said cam of the crankshaft lever,-a firing-pin armcarrying a firingpin removably but non-rotatively secured to thefirin'g-pin-actuating shaft and having a cam or projection to engage thefiring-arm slide, a vertically-movable spring-actuated slide havingaprojection in engagement with the said cam, and a spring-actuated searhaving a catch adapted for engagement with said firing-pin-arm to lockand hold the same in a retracted or cocked position, substantially asdescribed. w

6. In breech-loadin g ordnance, the combination with the breech-pieceadapted for carrying a sliding breech-block, and with thebreech-block,of a crank-shaft and lever adapted for raising and loweringsaid breech-block with relation to the breech-piece and having a camadapted to engage a cocking-lever carried by a shaft journaled in thebreech-block, a firing-pin-actuating shaft carrying a fir ngpin, acocking-lever, and a cam or pro ection,

on said shaft, a reciprocating slide located for longitudinal movementin the block, and

engagingwith a projecting arm on the firing shaft, a firing-springbearing against said slide to actuate the said firing-shaft, and

. pressed-position and thefiring-pin in a retracted, or a cookedposition, substantially as and for the purpose described.

7. In breech-loading ordnance, the combination with the breech-pieceadapted for carrying a vertically-sliding breech-block and with thevertically-sliding breech-block, of a crank-shaft journaled in thebreech-piece and carrying at its inner end a crank-arm in engagementwith, and adapted for moving said breech-block vertically and carryingat its outer end a coupling-lug or projection having abutting faces intrue radius to the axis of the shaft, and an actuating-lever havingremotely disposed abutments for alternately engaging theabutment-facesof the said coupling projection as the actuating-lever isreciprocated, the space between the abutments of said lever beinggreater than the width of the abutment projection upon the shaft,whereby the actuating-lever may have a free limited movement upon theshaft, substantially as described and for the purpose set forth.

' 8. In breech-loadingordnance,thecombination with the breech-pieceadapted for carrying a sliding breech-block, and with thevertically-sliding breech-block, of the breechblock-actuating shaftbearing a crank-arm at one end adapted for engaging and reciprocatingthe breech-block and having a cross-sectionally angular outer end with atransverse key-seat formed therein, an actuating-lever loosely mountedupon said shaft adjacent to the breech-piece and having a cam foractuating the breech-block mechanism and having remotely disposedradially-arranged abutments, a coupling-plate having a centraltransverse recess fitting the angular end of said shaft and having aV-shaped lug or projection at its-inner face to extend between theradially-arranged abutments and limit the free movement of theactuating-lever, the said plate having a central recess formed in itsperiphery extending into its central shaftengaging recess, and alocking-arm pivotedat one end in thecircumferential recess of saidcoupling-plate and having an arm to extend underneath said plate whenthe same is locked to the shaft and having a projection or key to enterthe key-seat in said shaft when said arm is thrown downward in a lockedposition, substantially as and for the purpose described.

9. In breech-loading ordnance, the combination with the breech-pieceadapted for carrying a sliding breech-block, and with thevertically-sliding breech-block, of a shaft transversel y j ournaled inthe breech-piece carrying a crank-arm at its inner end adapted forengaging and reciprocating the breech-block, a breech-block-actuatinglever carrying a cam for actuating the breech-block mechanism, acoupling removably, but non-rotatively, engaging said shaft and looselyengaging the actuating-lever to permit the same to have a limited freelateral movement with relation to the shaft, a firing-pin shaftremovably jourscribed.

10. In breech-loading ordnance, the combination with the breech-pieceadapted for car rying a sliding breech-block, and with thevertically-sliding breech-block, of a breechblock andfiring-pin-actuatingmechanismconsisting, essentially, of a shorthorizontal shaft journaled in the lower forward end of the breech-piececarrying a crank-arm at its inner endin engagement with the breech-blockfor actuating the same and having an actuatinglever provided with acocking-cam at its outer end, a firing-pin shaft journaled in the lowerforward end of the breech-block in substantially vertical alignment withthe breechblock-actuating shaft and having a cookinglever at its outerend in position to be acted upon by the cocking-cam upon theactuatinglever and carrying afiring pin arm with a removable firing-pinat its upper end and having at one side of said firing-pin arm, afiringspring-depressing cam, a spiral firing-spring seated in thevertical recessin the breech-block in alignment with the cam upon thefiringspring shaft, a vertically-reciprocating slide supported at itsupper end by said spring and having a projection at its lower end inengagement with said firing-pin'shaft cam, and a locking devicetherefor, consisting of a scar pivoted to the breech-block in positionand having a catch to engage a catch upon the firing-pin shaft, and asear-spring bearing against said sear and retaining it in normal lockedengagement with the firing-pin shaft,

substantially as'and for the purpose described.

11. In breech-loading ordnance, the combination with the breech-pieceadapted for carrying a sliding breech-block,and with thevertically-sliding breech-block, of a crank-shaft having a crank inengagement with and reciprocating said sliding breech-block and havingan actuating-lever removably secured thereto with a cam thereon toactuate the breech -block mechanism, of the firing-pin shaft G removablyjournaled in the side-walls of the breech-block and carrying thecockinglever at its outer end, and having the crosssectionally angularportion to receive the hub of the firing-pin and having thedetent-spring catch to engage one wall of the breech-block topreventlongitudinal movemeutof thesame, a firing-pin arm having across-sectionally angular axial recess in its hub and fitted upon theangular portion of the firing-pin shaft with the ends of its hub bearingagainst the inner faces of the side-walls of the breechblock, and afiring-spring to actuate said arm, and locking-mechanism to lock thefiring-pin shaft and firing-pin in a retracted position,

substantially as'described and for the purpose set forth. o

12. In breech-loading ordnance, the combination with the breech-pieceadapted for carrying a sliding breech-block, and with thevertically-sliding breech-block and mechanism for raising and loweringsaid breechblock with relation to the breech-piece, of a horizontalshaft removably'journaled in the lower forward end of the breech-blockat right-angles to the bore of the gun and having a cross-sectionallyangular portion intermediate to the side-walls of the breech-block, areduced longi-tndinally-recessed journal having abearing against theinner face of the side-wall of said breech-block, a detent-catch seatedin the longitudinal recess having a projection adapted for engagementwith the outer face of said side-wall, a firing-pin arm having a hubwith a cross-sectionally angular axial recess therein fitting theangular portion of said shaft and having a hearing at its ends againstthe inner faces of the siderying a sliding breech-block of thevertically sliding breech-block sliding in said breech-piece and havinga stop-groove formed in the outer face of its side wall, a crank-shaftjournaled in the lower forward end of the breech-piece and having acrank in engagement'with and reciprocating the breech-block, said shaftbeing provided at its outer end with an actuating-lever; a stop-pinseated in a shouldered recess in the side wall of the breech-piece and aresilient detent catch se-- cured to said stop-pin and adapted forlateral movement with relation thereto and for engagement with theshouldered portion-of the recess for preventing longitudinaldisplacement of the stop-pin,said stop-pin being adapted to extend intothe breech-block to limit the vertical movement of the breechblock withrelation to said breech, substantially as described.

14. In breech-loading ordnance, the combination of the breech-pieceadapted for carrying a sliding breech-block and having a transversestop-recess extending entirely through 'oneof its side-walls to form abearing for a stop. and having a series of remotely disposed catchnotches in said bearing, a breech-block having a stop-groove formed inone side thereof in alignment with the stop-bearing in the breech-piece,a longitudinally-recessed stoppin extended through the bearing in thebreech-piece and entering the stop-groove in the breech-block to limitthe movement of the breech-block with relation to the breech, and

